Outdoor display device for sequentially displaying a series of panels

ABSTRACT

Outdoor traveling display device for a series of panels having signs thereon, in which panels are suspended in end-to-end relation from an endless chain trained in a horizontal plane adjacent and beneath the top wall of a housing for the device. The chain is driven with a series of equally spaced dwells, to index a panel behind a viewing screen of the device and hold the panel in position for viewing for a preselected time interval, and then index a next succeeding panel into position for viewing.

United States Patent 1191 Burns 1451 July 23, 1974 OUTDOOR DISPLAY DEVICE FOR SEQUENTIALLY DISPLAYING A SERIES OF PANELS [75] Inventor: Robert G. Burns, Sioux Falls, S.

Dak.

[73] Assignee: Pylon Incorporated, Sioux Falls, S.

Dak.

[22] Filed: June 22, 1972 [21] Appl. No.: 265,262

[52] US. Cl. 40/32 [51] Int. Cl. G091 11/28 [58] Field of Search 40/28 R, 30-33,

[56] References Cited UNITED STATES PATENTS 995,287 6/1911 Phillips 40/97 l,387,635 8/1921 Aisenberg 40/32 1,842,422 1/1932 O'Shea 40/32 2,102,243 12 1937 Van Deventer 40/32 3,187,451 6 1965 Fontaine 40 32 3,336,687 8/1967 Fontaine 40 32 3,664,050 5/1972 Manzano 40 32 Primary ExaminerRobert W. Michell Assistant ExaminerA. J. Heinz Attorney, Agent, or Firm-Hill, Gross, Simpson, Van Santen, Steadman, Chiara & Simpson [5 7] ABSTRACT Outdoor traveling display device for a series of panels having signs thereon, in which panels are suspended in end-to-end relation from an endless chain trained in a horizontal plane adjacent and beneath the top wall of a housing for the device. The chain is driven with a series of equally spaced dwells, to index a panel behind a viewing screen of the device and hold the panel in position for viewing for a preselected time interval, and then index a next succeeding panel into position for viewing.

9 Claims, 7 Drawing Figures OUTDOOR DISPLAY DEVICE FOR SEQUENTIALLY DISPLAYING A SERIES OF PANELS FIELD OF THE INVENTION Outdoor display device for signs, periodically bringing signs in front of a viewing screen and holding the signs behind the screen for a preselected time interval.

SUMMARY, ADVANTAGES AND OBJECTS OF INVENTION The invention generally consists in the suspension of connected flexible signs from an endless chain driven step-by-step in accordance with the lengths of the signs and trained in a sinuous path, to increase the effective length of the chain and the number of signs that may be suspended therefrom. The endless chain is driven in a horizontal plane through a motor and clutch, periodically deenergized as a sign is brought behind a viewing screen in the housing for the device. The signs are detachably hooked to the chain and are detachably connected in end-to-end relation with respect to each other by slide fasteners or other suitable fastening means and the chain is drivenstep-by-step, to index a panel behind the viewing screen, hold it in position for a set interval and then index a next succeeding panel in registry with the screen. A cam driven at a constant speed by a motor, separate from the drive motor for the chain establishes an energizing circuit to the clutch. Stop actuators spaced along the chain deenergize the clutch and accommodate reenergization of the clutch by the cam.

An advantage of the presentinvention is that a series of different advertising panels may be placed outdoors, protected from the weather, and be successively viewed through a viewing screen, by cyclically bringing a panel in front of the viewing window and then bringing a next succeeding panel in front of the window by a simplified form of suspension and drive means for the panels, which may continuously operate with little, if any, attention.

Another advantage in the invention is the construction of the device so the panels may be detachably connected for movement together and may readily be changed with the minimum amount of time and effort.

t and reliability and efficiency in operation.

Other objects, features and advantages of the invention will be readily apparent from the following description of a preferred embodiment thereof, taken in conjunction with the accompanying drawings, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an outdoor display device constructed in accordance with the principles of the present invention.

FIG. 2 is a transverse sectional view taken substantially along line 2-2 of FIG. 1.

FIG. 3 is a generally diagrammatic view, looking upwardly toward the endless suspension and drive chain for the panel and diagrammatically illustrating the drive to the chain and the tension means therefor.

FIG. 4 is a fragmentary vertical sectional view taken substantially along line 4--4 of FIG. 3 and illustrating the take-up for the chain and suspension means for suspending the panels from the chain. 7

FIG. 5 is a fragmentary sectional view taken substantially along line 55 of FIG. 3, illustrating the idler sprockets supporting the chain intermediate the ends of the runs thereof.

FIG. 6 is a fragmentary sectional view taken substantially along line 66 of FIG. 5, illustrating the drive to the drive sprocket; and

FIG. 7 is a schematic view of the electrical circuit for effecting and controlling the drive to the endless chain and panels.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION In FIGS. 1, 2 and 3 of the drawings, 1 have shown a display device embodying the principles of the present invention and including a housing 10, shown as being of a generally rectangular box-like form and supported on a base and pedestal 11. The base 11 has a pair of parallel spaced side frame members 12 extending upwardly therefrom, connected together by a top beam 13 extending across said housing and forming a support for the operating mechanism for the device. A bottom beam 14 connects the side frame members at their lower ends and extends along the bottom of the housing 10.

The housing 10 may be welded or otherwise secured to the side frame members 12, to beam 13 and bottom beam 14, and may extend from opposite sides thereof and is shown in FIGS. 1 and 2 as having a front opening 15 shown as being rectangular in form and closed by a viewing screen 16, which may be glass or transparent plastic, and forms a screen, in back of which are positioned advertising panels 17, successively brought into registry with said screen and then held in position behind said screen, to enable the successive panels to readily be viewed. The housing 10 also has an access door 19 in the rear wall thereof, enabling panels to be hooked or clipped to an endless flexible drive member, shown as being in the form of a chain 20, guided to have a viewing run 21 extending parallel to the front of the screen 16 and an access run 22 extending parallel to the back wall of the housing and access door 19, and guided to travel in a generally elongated sinuous path between said viewing and access runs, to provide sufficient length of chain to accommodate a plurality of panels 17 to be suspended therefrom in end-to-end relation with respect to each other.

The endless chain 20 may be a conventional form of roller chain in which the pintle pins of the chain (not shown) are in the form of sleeves, to accommodate the shanks of screw eyes 23 to pass through said sleeves to suspend the eyes of said screw eyes from said chain.

Nuts 24 may be threaded on the shanks of said screw eyes and suitably locked thereto, to retain said screw eyes to travel with said chain (FIGS. 4 and 5).

The panels 17 may be flexible panels, sufficiently flexible to conform to the path of travel of the chain, as changing its direction about a series of direction changing and supporting idlers 25, adjacent opposite ends of the housing 10. The panels 17 are preferably made from a plastic material, which may be transparem, and may be illuminated by back lighting, by a series of parallel vertically spaced horizontal fluroescent tubes 27. The panel also may be illuminated by a suitable light 29 at the outside of the housing and extending along the top of the panel, and diagrammatically illustrated in FIG. 7. Said panels, therefore, need not necessarily be transparent, particularly where illuminated by external lights.

As shown in FIG. 4, the panels are hooked to the eyes of the screw eyes 23 by books 30 extending through the top marginal surfaces of the panels and upwardly therefrom. While the panels are herein shown as being hooked to the eyes of the screw eyes 23, they instead may be clipped to the eyes of said screw eyes by snap clips (notshown) or any other conventional fastening means. The panels 17 are also shown in FIG. 4 as connected together in end-to-end relation with respect to each other, by slide fasteners 31 to provide in effect a continuous panel with different views or advertisements equally spaced therealong and successively indexed 'in back of the screen 16 and illuminated by backlighting provided by the vertically spaced fluorescent tubes 27.

As shown in FIGS. 2 and 6, the beams 13 and 14 are generally l-I-shaped in cross section and form supports adjacent the lower ends of the legs thereof within the housing 10, for the horizontal legs 32 of a frame structure 33 supporting the fluorescent tubes 27 at their ends. The frame structures 33 and legs 32 may be spaced adjacent opposite ends of the housing behind the viewing screen 16 and within the orbit of the endless chain to support the tubes to illuminate in back of the entire area of the panels, as passing behind the viewing screen 16.

A horizontal plate 35 is suspended from the legs 32 of the frame structure 33 by threaded rods or bolts 37 (FIG. 2). The plate 35 forms a support for the idlers at one end of the path of travel of the endless chain, supporting and changing the direction of the chain. The plate 36 is suspended from a plate 41 welded or otherwise secured to the bottoms of the lower legs of the top beam 13, as by suspension rods 43 (FIG. 6). The plate 36 forms a support for the idlers 25 at the opposite end of the path of travel of the endless chain.

An intermediate plate 39 may also be suspended from the top beam 13 in a suitable manner through threaded rods or any other suitable means (not shown), in the plane of the plates 35 and 36 and in parallel spaced relation with respect thereto. Said intermediate plate forms a support for a series of support idlers 40 freely rotatably mounted on headed pins 38, shown in FIG. 5 as being threaded in the plate 39 and depending therefrom, with the heads thereof retaining the idlers in fixed relation with respect to the bottom of the plate 39, for free rotation with respect thereto. Bearings (not shown) may journal said support idlers on said pins.

The idlers 40 are in the form of sprockets meshing with the chain 20, with one idler 40 meshing on one side of a run of said chain and another idler 40 meshing with the opposite side of the same run of said chain, and spaced longitudinally therealong, to suppport the chain intermediate its ends and prevent sagging thereof, as passing from one end of the housing to the other. Two idlers are provided for supporting each run of the chain intermediate its ends and all of the idlers are of the same construction and mounted to depend from the plate 39 in a similar manner.

The chain is supported at the opposite ends of its horizontal runs by the direction changing idlers 25, suspended from the respective plates 35 and 36, in the same manner the idlers 40 are suspended from the plate 39.

Suitably mounted on the top of the plate 36 is a motor 44, clutch 45, driven therefrom and a speed reducer 46 driven by said clutch (FIG. 6). The motor, clutch and speed reducer are shown as carried in separate housings, connected together in end-to-end relation with respect to each other, and may be of various commercial forms well-known to those skilled in the art, so need not herein be shown or described in further detail. The speed reducer 46 has a vertical drive shaft 47 depending from its housing, through an opening 48 in the plate 36, and has a sprocket 49 keyed or otherwise secured to its lower end. Nuts 50 threaded on the upper ends of the threaded rods 43 are provided to suspend said rods from the plate 41, and to adjust the position of the plate 36, motor, clutch and speed reducer, to bring the drive sprocket 49 and idler sprockets 25 in horizontal alignment with the intermediate support sprockets 40. Lock nuts 51 threaded on the rods 43 may be engaged with the bottom of the plate 41 to retain the plate 36 and motor, clutch and speed reducer in the proper position.

The motor 44 may be a constant speed continuously driven electric motor of a well-known form, while the clutch 45 may be a commercial form of electrically energizable clutch, energized to provide a drive connection from said motor 41 to the speed reducer 46. The speed reducer 46 may be a conventional form of right angle drive type of reducer, providing a reduced speed drive for the depending drive shaft 47. Beneath the plate 35 and between certain of the idlers 25 and in horizontal alignment therewith, is a take-up idler 53. The take-up idler 53 is suspended from a take-up arm 54 pivoted intermediate its ends, to the top side of the plate 35 on a vertical pivot pin 55. A shaft 56 depends from the free end of the arm 54 and extends through an arcuate slot 57 formed in the plate 35, and forms a bearing mounting for the tension idler 53.

The idler 53 is biased to maintain tension on a chain 20 by a weight 59 suspended from the flexible cable 60, through a screw eye 61. The flexible cable 60 passes upwardly from the weight 59 about an idler pulley 62, disposed beneath the plate 35, and rotatably supported between a pair of depending bracket legs 63 for rotation about a horizontal axis. From the idler 62, the flexible cable 60 extends inwardly to and has operative connection with the shaft 56 to bias the arm 54 in a direction to maintain the chain 20 under a preselected tension.

The pivoted arm 54 is diagrammatically shown in FIG. 7 as having an enlarged end 64 extending from the pivot pin 55, in a direction opposite from the tension idler 53 and as having an outer camming face 65 engaged by a follower roller 66 of a safety control switch 67. Upon excess slack on the chain and pivotal movement of the arm 54in one direction, the camming face 65 will effect closing of the switch 67 and energization of a relay coil 68. This will open the contacts 70, of a safety latching relay 71 (FIG. 7) and thereby break the circuit to the clutch 45, and stop the drive to the chain 20.

In cases where the chain 20 may jam or be overloaded, causing an excessive tension on said chain, the arm 54 will pivot in an opposite direction, shown in FIG. 7 as being a counterclockwise direction, to effect closing of the switch 67 and deenergization of th clutch 45 in the manner just described. j

Referring now in particular to FIG. 7, schematically illustrating the electric circuit controlling operation of the device, the control of power to the sign may be by a timer 69, which may be of a type enabling the selection of any period of operation of the sign within a twenty-four hour period. The timer 69 may be a commercial timer of a form well-known to those skilled in the art and is no part of the present invention, so need not herein be shown or described further.

All power to the internal lights 27 and the external lights 29 is through a photoelectric control 72. This control has the customary shade (not shown) which may be adjusted to determine when the lights turn on and off. if it is desired that the lights be on at all times the sign is operating, the opening (not shown) in the control is covered. The photoelectric control 72 may be of various commercial forms suited for the purpose and is no part of the present invention so need not herein be shown or described further.

Turning of the external lights 29 on may be under the control of a manually operated switch 72a. A manually operated switch 72b is provided to control the turning on of the lights 27 within the housing in back of the panels, traveling along the viewing run 21 of the chain.

A manually operable motor switch 73 is provided in the circuit from the timer 69 to the motor 44 to energize said motor 44 and cause said motor to be continuously driven as long as said switch 73 is in its on position.

A cam motor 75 is provided to drive a disk cam 76 on a shaft 77 of said motor. The cam motor is energized by closing of a manually operable cam motor switch 79, to drive the cam 76 to turn at a speed, which may be one revolution per minute. The cam 76 has a plurality of cam lobes 80 extending from the surface thereof, effective to momentarily close a switch arm 81 and effect energization of a relay coil 82 of a latching relay 82a, and close switch contacts 83 of said relay and effect energization of the clutch 45 through a clutch control switch 89, the latching relay 71, the contacts 83 and a conductor 84 to thereby engage the clutch. The contacts 83 are start/stop contacts of the latching relay and latch in a closed position upon energization of the coil 82.

In starting the circuit, the motor drive switch 73, the cam motor switch 79, the clutch control switch 89 and a reset switch 91 are closed.

Upon closing of the contacts 83 by energization of the relay coil 82 as the switch 81 is momentarily closed by the cam 76, the drive to the endless chain will be effective until a switch actuator cam 85 on the endless chain 20 momentarily closes a stop switch 86. This will energize a relay coil 87 of the latching relay 82a, and

cause the contacts 83 to latch in an open position. The clutch 45 will then be deenergized and the drive to the chain 20 will stop. The cam motor 75, however, will continue to drive the cam 76 and momentarily close the cam switch 81 and energize the relay coil 82 of the start/stop relay 82a and latch the contacts 83 of said relay into their closed position, to then energize the clutch 45, to continue the drive to the chain 20. Cam actuator lugs 85 are spaced along the chain 20 in accordance with the length of the panels carried by said chain, to periodically deenergize the clutch 45, as a panel is moved into position behind the viewing screen 16.

The drive for the sign and stopping thereof is thus attained by alternately energizing the two coils 82 and 87 of the latching relay 820, the contacts of which make and break a circuit to the clutch 45 and thus energize and deenergize said clutch to effect engagement or disengagement of the clutch to bring a panel in front of the viewing screen 16 and hold the panel in position to be viewed.

The cam 76 is shown as having six equally spaced lobes 80 thereon and in the present instance is driven to rotate at one revolution per minute. The chain 20 also has equally spaced actuator cam lugs 85 spaced therealong in accordance with the length of the panels and the number of panels to be viewed. There will thus be six energizing cycles per minute for the clutch 45, allowing approximately 5 seconds to transport a panel in front of the viewing screen 16 and leaving 5 seconds during which a panel is stopped in viewing position.

A nonnally open jog switch 88 is provided in the circuit to the clutch 45 and bypasses the contacts 83 of the start/stop latching relay 82a to facilitate the changing of panels. When the jog switch is closed and the cam motor switch 79 and a clutch control switch 89 are closed, the drive will continuously operate and an energizing circuit will be established to the clutch 45 through the clutch switch 89, safety relay contacts of the latching relay 71 jog switch 88and conductor 84. During operation of the jog switch 88, the cam motor switch 79 should be turned off before using the jog switch, to prevent the cam 76 from closing the switch 81, and thereby prevent starting of the drive chain 20 as the cam rotates. As the cam motor switch 70 is turned off, the jog switch 88 may be operated to start and stop the drive as required to enable the advertising panels to be changed.

A reset switch 91 is connected from a line 92 leading from the timer 69 to a relay coil 93 and is momentarily closed, to energize said coil and latch the safety relay switch contacts 70 closed and thereby provide an energizing circuit to the clutch 45 through the clutch control switch 89, contacts 70 of relay 71, contacts 83 of relay 71 and the conductor 84, and thereby reset the system and start travel of the drive chain 20.

When it is desired to operate the sign, it is merely necessary to close the switches 72a and 72b, or to only close the switch 72a to at least back light the panel by the fluorescent tubes 27, under control of the photoelectric control 72. Assuming the timer 69 has been set to operate the sign for a predetermined time interval, the cam motor switch 79, the motor drive switch 73 and the clutch control switch 89 are closed, the reset switch 91 is momentarily closed. The relay coil 93 will be energized to close the safety contacts 70 which will latch closed. This will provide a circuit to the stop/start contacts 83 of the latching relay 82a. The clutch 45 will then be in condition to be energized as the cam lobe 80 momentarily closes the switch 81 to energize the relay coil 82 and latch the contacts 83 into their closed positrons.

The chain 20 will then be driven to periodically bring the panels 17 having signs thereon in front of the viewing screen 16. The drive chain will stop its travel as a stop actuator lug 85 closes the switch 86 to energize the relay coil 87 of the latching relay and latch the contacts 83 in their open positions. After a time delay sufficient to enable the sign on the panel to be viewed, a cam lobe 80 will again close the switch 81 and energize the relay coil 82 of the latching relay 82a and complete an energizing circuit to the-clutch 45 through the clutch control switch 89, safety relay contacts 70, contacts 83, the latching relay 82a and conductor 84 leading to the clutch 45, it being understood that the return from the clutch 45 is through a conductor 93 connected with the timer 69.

The sign may then continue to operate in the manner just described bringing a next adjacent display panel in front of viewing screen 16, and stopping the panel in front of said screen for a sufficient length of time to enable the sign to be viewed and comprehended, and then bringing a next succeeding panel in front of the viewing screen. I

If, however, the chain should jam or become unduly slack, the takeup arm 54 will move in either a clockwise or counterclockwise direction, depending upon tension conditions of the chain, to close the switch 67 and energize the relay coil 68 and latch the latching contacts 70 of the safety relay 71 open. When the slack or overload conditionsare cured, operation of the system is continued by momentarily closing the reset switch 91 and again energizing the relay coil 93, to latch the safety relay contacts 70 closed.

It will further be understood that control of travel of the sign can be manually by operation of the jog switch 88 bypassing the start/stop relay contact 83 and energizing the clutch through the clutch control switch 89, safety contacts 70, the jog switch 88 and conductor 84.

I claim as my invention:

1. In a display device for sequentially displaying advertisements and the like,

a housing having a top, a back, a front, and a viewing screen extending along the front thereof,

an endless flexible drive member within said housing guided for movement within said housing including a path extending along the back of said viewing screen,

a series of panels,

means detachably suspending said panels from said flexible drive member in end-to-end relation with respect to each other to travel along said screen for display,

a drive motor,

drive means driven by said drive motor at a uniform rate of speed effecting a drive from said motor to said flexible drive member,

a series of lights mounted within the housing opposite the screen to illuminate the panels as brought in registry with the screen,

control means for said drive means effective to bring a panel in alignment with said screen and hold the panel in position with said screen for a preselected time unit, and then bring a next adjacent panel in alignment with the screen to successively display all of the panels on said drive member,

said control means including a continuously operating cam motor operating an energizing circuit to said drive motor continuously driving said drive motor,

a clutch drivingly connecting said drive motor to said flexible drive member,

cam means operated by said cam motor and coupled to said clutch for engaging it,

stop means on said flexible drive member operable to disengage said clutch to effect the holding of a panel in front of said screen,

wherein the stop means comprises a stationary switch and separate stop actuators spaced along said flexible drive member and operable to actuate said switch to effect disengagement of said clutch, and provide a dwell in the travel of said flexible drive, and

wherein the cam means is effective to reengage said clutch and provide a drive to said flexible drive member.

2. The display panel of claim 1,

wherein the clutch is an electrically energized clutch,

and including a manually operable switch for energizing said motor, and

wherein the flexible drive device is an endless chain trained in a generally sinuous path and having a display run extending behind said screen and meshed with idler sprockets depending from the top portion of said housing and rotatable about vertical axes,

wherein at least one of said sprockets is a tension idler,

wherein means are provided to bias said tension idler to maintain tension on said chain, and

wherein other means are provided, actuated by said biasing means to deenergize said clutch upon excessive slack or overload of said chain.

3. The display device of claim 2,

wherein the biasing means for taking up tension on the chain comprises a pivoted arm forming a mounting for said tension idler and having a camming surface, and

wherein a safety control switch is engaged by said camming surface and normally maintained in an open position thereby and moved into position to break a circuit to said clutch upon excessive slack or overload of said chain.

4. The display device of claim 3, including stop actuators spaced along said chain,

a stop switch controlling energization of said clutch and moved into position to deenergize said clutch and stop travel of said chain during predetermined cyclical periods in travel of said chain.

5. The display device of claim 4,

wherein the cam operates'a cam switch controlling energization of said clutch and reenergizing of said clutch after actuation of said stop switch by a stop actuator.

6. The display device of claim 2 wherein the flexible drive device is an endless chain trained to travel in a horizontal plane in a generally sinuous path and having a display run extending along and behind said screen,

wherein idler sprockets depending from the top portion of said housing and mounted for rotation about vertical axes mesh with and support said chain,

wherein at least one of the sprockets is a tension idler,

wherein means are provided to bias said tension idler to maintain tension on said chain,

wherein the clutch is an electrically energized clutch,

engaged when energized and including a switch for energizing said cam motor when closed,

a motor switch for energizing said drive motor whe closed,

a latching relay having contacts having energizing connection with said clutch when closed,

a clutch control switch completing a circuit to said contacts of said latching relay,

a cam switch momentarily closed to complete an energizing circuit to said latching relay, to effect closing of the contacts thereof, and the energization of and engagement of said clutch,

a stop switch normally open and effective to complete a circuit to said latching relay to open the contacts of said latching relay and to deenergize and disengage said clutch, and

stop actuator lugs spaced along said endless chain in accordance with the length of the panels displayed, to close said stop switch and open the contact to said relay to effect the stopping of a panel in registry with said screen.

7. The display device of claim 6, including a safety latching relay in the circuit from said clutch control switch to the contacts of said first mentioned latching relay,

a reset switch effecting the closing of said safety latching relay,

a safety control switch effecting the opening of the contacts of said latching relay and disengagement of said clutch,

and means actuated by said biasing means for said tensioning idler, effective to close said safety control switch and open the contacts of said safety latching relay upon excessive slack or on overload of said chain.

8. The display device of claim 1, including a tensioning device maintaining a predetermined tension of said flexible drive member and a safety control switch in a circuit to said clutch and actuated by said tensioning device to deenergize said clutch and stop the drive to said flexible drive member, upon the overloading of said flexible drive member or the formation of slack therein.

9. The display device of claim 1, including a relay connected in the circuit to said clutch and having contacts closed by said cam means,

wherein the switch is effective to open said contacts of said-relay,

wherein the stop actuators spaced along said flexible drive member are effective to close contacts of said relay to stop the drive to said flexible drive member, and

wherein closing of said contacts of said relay and energization of said clutch is effected upon continued operation of said cam means. 

1. In a display device for sequentially displaying advertisements and the like, a housing having a top, a back, a front, and a viewing screen extending along the front thereof, an endless flexible drive member within said housing guided for movement within said housing including a path extending along the back of said viewing screen, a series of panels, means detachably suspending said panels from said flexible drive memBer in end-to-end relation with respect to each other to travel along said screen for display, a drive motor, drive means driven by said drive motor at a uniform rate of speed effecting a drive from said motor to said flexible drive member, a series of lights mounted within the housing opposite the screen to illuminate the panels as brought in registry with the screen, control means for said drive means effective to bring a panel in alignment with said screen and hold the panel in position with said screen for a preselected time unit, and then bring a next adjacent panel in alignment with the screen to successively display all of the panels on said drive member, said control means including a continuously operating cam motor operating an energizing circuit to said drive motor continuously driving said drive motor, a clutch drivingly connecting said drive motor to said flexible drive member, cam means operated by said cam motor and coupled to said clutch for engaging it, stop means on said flexible drive member operable to disengage said clutch to effect the holding of a panel in front of said screen, wherein the stop means comprises a stationary switch and separate stop actuators spaced along said flexible drive member and operable to actuate said switch to effect disengagement of said clutch, and provide a dwell in the travel of said flexible drive, and wherein the cam means is effective to reengage said clutch and provide a drive to said flexible drive member.
 2. The display panel of claim 1, wherein the clutch is an electrically energized clutch, and including a manually operable switch for energizing said motor, and wherein the flexible drive device is an endless chain trained in a generally sinuous path and having a display run extending behind said screen and meshed with idler sprockets depending from the top portion of said housing and rotatable about vertical axes, wherein at least one of said sprockets is a tension idler, wherein means are provided to bias said tension idler to maintain tension on said chain, and wherein other means are provided, actuated by said biasing means to deenergize said clutch upon excessive slack or overload of said chain.
 3. The display device of claim 2, wherein the biasing means for taking up tension on the chain comprises a pivoted arm forming a mounting for said tension idler and having a camming surface, and wherein a safety control switch is engaged by said camming surface and normally maintained in an open position thereby and moved into position to break a circuit to said clutch upon excessive slack or overload of said chain.
 4. The display device of claim 3, including stop actuators spaced along said chain, a stop switch controlling energization of said clutch and moved into position to deenergize said clutch and stop travel of said chain during predetermined cyclical periods in travel of said chain.
 5. The display device of claim 4, wherein the cam operates a cam switch controlling energization of said clutch and reenergizing of said clutch after actuation of said stop switch by a stop actuator.
 6. The display device of claim 2 wherein the flexible drive device is an endless chain trained to travel in a horizontal plane in a generally sinuous path and having a display run extending along and behind said screen, wherein idler sprockets depending from the top portion of said housing and mounted for rotation about vertical axes mesh with and support said chain, wherein at least one of the sprockets is a tension idler, wherein means are provided to bias said tension idler to maintain tension on said chain, wherein the clutch is an electrically energized clutch, engaged when energized and including a switch for energizing said cam motor when closed, a motor switch for energizing said drive motor when closed, a latching relay having contacts having energizing connectIon with said clutch when closed, a clutch control switch completing a circuit to said contacts of said latching relay, a cam switch momentarily closed to complete an energizing circuit to said latching relay, to effect closing of the contacts thereof, and the energization of and engagement of said clutch, a stop switch normally open and effective to complete a circuit to said latching relay to open the contacts of said latching relay and to deenergize and disengage said clutch, and stop actuator lugs spaced along said endless chain in accordance with the length of the panels displayed, to close said stop switch and open the contact to said relay to effect the stopping of a panel in registry with said screen.
 7. The display device of claim 6, including a safety latching relay in the circuit from said clutch control switch to the contacts of said first mentioned latching relay, a reset switch effecting the closing of said safety latching relay, a safety control switch effecting the opening of the contacts of said latching relay and disengagement of said clutch, and means actuated by said biasing means for said tensioning idler, effective to close said safety control switch and open the contacts of said safety latching relay upon excessive slack or on overload of said chain.
 8. The display device of claim 1, including a tensioning device maintaining a predetermined tension of said flexible drive member and a safety control switch in a circuit to said clutch and actuated by said tensioning device to deenergize said clutch and stop the drive to said flexible drive member, upon the overloading of said flexible drive member or the formation of slack therein.
 9. The display device of claim 1, including a relay connected in the circuit to said clutch and having contacts closed by said cam means, wherein the switch is effective to open said contacts of said relay, wherein the stop actuators spaced along said flexible drive member are effective to close contacts of said relay to stop the drive to said flexible drive member, and wherein closing of said contacts of said relay and energization of said clutch is effected upon continued operation of said cam means. 